parallel, parallel_compatibility, concurrency and concurrency_simultaneous test suites are not adding much to the coverage for mobile while adding to the time it takes to run the variants. Mobile SE is not intended to run parallel and concurrent operations and hence running these suites over it isn't building confidence in it's stability any more than the other core tests.

For instance, on RHEL 6.2 (mobile), following are the runtimes during my trial runs when excluding map_reduce tests (SERVER-35473):
concurrency – 1.5 hours
concurrency_simultaneous – 3.5 hours